Holmz Skool'in Lesson in Noise and SPL - LotusTalk - The Lotus Cars Community
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post #1 of 1 (permalink) Old 08-09-2008, 02:16 AM Thread Starter
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Holmz Skool'in Lesson in Noise and SPL

Welcome the first Holmz-Skoolin class.
Todays lesson is in Noise and sound pressure - relative to the noise level in a Lotus.

A year or so ago I was doing some work and my neighbor Richard asked, "What-cha doin?".
I said, "Well I am sound proofing my wife's office".
He said, "What do you know about it?"
<Conversation ensued>
I have a few books on the subject "Handbook for sound engineers" by Ballou, and "Sound system Engineering" by Davis and Davis, which recommend.
Turns out Richard has a background in recording and had a couple of RadioShack sound pressure meters, so he gave me his old analogue one to use shown Here.

In This Link is the OSHA and NIOSH recommendations for maximum daily exposure to SPL (Sound Pressure Level).
The NOISH is much lower, and I think likely a better value to use.

The bottom line of the study (in the above link) is that below 85dBA the Bose noise reduction headphones give ~13dB cancellation, but there is little data in how well they cancel noise above that level, which I would expect is limited for safety and legal reasons.

So here is the data (below), and adding some other measurements from aftermarket exahust and sport versus touring package would be useful.

If you want to know how loud the car is get a PSL meter and turn up the TV till you get to the same level and then see how that is... Or take measurements in your current car and then determine how much more pain you can take.

I find it loud and after a 30 minute drive have the ear that is closest to window being a bit sore without protection.
On a long trip many people recommend something.
On the other hand you need to hear some noises, and using the ears for mirrors doesn't work when the ears are plugged, and it may not be legal to have your ears plugged in some regions/states.

I have the sensaphonics , but had some Shure foam sleeves (ear pieces) that worked just as well for noise reduction prior to the sensaphonics. Audiophiles can debate which is better for music.
The Sensaphonics also makes ear pieces with fixed (10, 15 and 20dB )attenuation for motorcyclists musicians etc These.
I also carry some single use foam ear plugs in the car for passengers that want to use them.
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